Abstract:

Objective Towards full understanding of characteristics of jacquard woven fabrics with double warps and quadruple wefts for double-weft color gradation, construction of jacquard woven fabric models are proposed involving six primary color threads (red, yellow, green, blue, black, and white), with a double-layer structure which enables independent regulation over the coloring and the backing warp and weft threads. Five key factors are taking into consideration in the development and calculation of double-weft color gradation compound weaves for color expression, namely the weave repeat number N, the step number S, the quantity of its available value ${Q}_{{S}_{N}}$QSN, the transition speed M, and the quantity of available interlacing for stitching at the stitching positions Q_IS. This research aims to provide insights for the color space construction and jacquard structure modeling with double warps and quadruple wefts for double-weft color gradation.

Method In order to construct the fabric model, 2 sets of achromatic threads and 4 sets of chromatic threads were placed in the warp and weft configuration, and the face and back weaves, as well as the relationship between the face and back layers were arranged to form double-weft color gradation compound weaves with their quantities calculated. Eventually, 12-thread 7-step sateen was selected as basic weave for shaded face weave-database and full-color face weave-database establishment. Double-weft color gradation compound weaves for validation were employed for the EAT sample simulation, enabling comparison and analysis of the structural coloring characteristics of jacquard structure with double warps and quadruple wefts for double-weft color gradation according to technique parameters given.

Results 720 varieties of jacquard structure model were found available with double warps and quadruple wefts based on six primary color threads. 3 warp and weft color configurations were formed according to the arrangement of achromatic and chromatic warp and weft threads, generaing 8 types of warp and weft color configuration on the face layer, and maximizing the structural coloring space, 2 sets achromatic warp and 4 sets chromatic weft were employed to the construction of jacquard structure model with double warps and quadruple wefts for double-weft color gradation. Further, 12 structural coloring series of jacquard structure model with double warps and quadruple wefts on double-weft gradation were formed under the interlacement of single achromatic warp and double chromatic weft. The maximum quantity of compound weaves applying shaded weaves is $12\times {Q}_{S{W}_{M=1}}^{4}\times [1+4({2}^{N}-1)+4({2}^{N}{-1)}^{2}]$12×QSWM=14×[1+4(2N-1)+4(2N-1)2], while that employing full-color face weaves is $12\times {2}^{4{N}^{2}-8N}\times [1+4({2}^{N}-1)+4({2}^{N}{-1)}^{2}],$12×24N2-8N×[1+4(2N-1)+4(2N-1)2], then more than 1.565×10³² and over 5.491×10²² double-weft color gradation compound weaves were obtained when weave repeat N equals to 5, and transition speed M equals to 1, respectively. Sample simulation of double-weft color gradation compound weaves were used for validation, on one hand, with the application of double-layer structure, face layer covers back layer completely, and thread interchanging within the structure makes it possible for double layer to connect without self-stitching, on the other hand, both juxtaposition and covering features expressed within the adjacent two wefts of the compound shaded weaves, while any adjacent two wefts of the compound full-color weaves juxtapose permanently, it is reducing the slippage of adjacent threads that is beneficial to the stabilization of woven structure, what's more, obvious oblique texture occurred on the sample surface because of the influence of start point and step number S of basic weave, configuration ratio of face wefts as well as lightness variation of warp and weft.

Conclusion In jacquard structure model with double warps and quadruple wefts for double-weft gradation, the application of full-color face weave-databases regulates the status of the adjacent face wefts within double-weft color gradation compound weaves, conducing to the stability of structural coloring, when weave repeat N to take the minimum value, the maximum quantity of double-weft gradation compound weaves reaches 10³² and 10²² when shaded face weave-database and full-color face weave-database are implemented respectively. What's more, the employment of full-color technical points is conductive to the juxtaposition of face wefts, thus, this study contributes to the structural coloring space construction and optimization of jacquard structure model with double warps and quadruple wefts for double-weft color gradation.

Key words: fabric design, digital jacquard, double warps and quadruple wefts, fabric structure, double-weft color gradation, structural coloring, color scheme